1. Field of the Invention
The present invention relates to a combustion-type power tool, and more particularly, to such power tool capable of driving a fastener such as a nail, an anchor, and a staple into a workpiece.
2. Description of Related Art
In a conventional combustion-type driving tool such as a nail gun, a combustion chamber is formed when a push member is pushed a predetermined distance. Then, a mixture of air and gaseous fuel injected into the combustion chamber is ignited by a spark at an ignition plug to cause gas expansion in the combustion chamber, which in turn causes a linear momentum of a piston. By the movement of the piston, a nail is driven into a workpiece.
Such conventional combustion-type nail gun is described in U.S. Pat. No. 5,197,646. In U.S. Pat. No. 5,197,646, a man cannot turn on a trigger for turning on the ignition plug without pushing a push member.